Respiratory studies on two small freshwater amoebae

The changes in respiration rate and mean cell volume induced by temperature within the range 10°C–25°C were investigated in two small species of freshwater amoebae,Saccamoeba limax Page andVannella sp. Mean cell volume varied in response to temperature, with maxima at 20°C inVannella sp. (10.15× 10³ (±1.80)m³ and 15°C inS. limax (9.08×10³ (±0.93)m³. Respiration rate increased over the temperature range investigated. The highest rates and the greatest rate of increase between temperatures occurred inVannella sp. Q₁₀ ranged between 0.12 and 1.33 inS. limax and between 1.77 and 7.36 inVannella sp. A regression of log oxygen uptake versus log cell volume incorporating the data of the present investigation and the data of other workers on amoeba respiration is presented, and the ecological significance and application of such data discussed.